Shrek! is a fantasy comedy picture book published in 1990. Written and illustrated by American book writer and cartoonist William Steig, it is about a repugnant green monster who leaves home to see the world and ends up marrying an ugly princess. The book was generally well received upon publication, with critics praising the illustrations, originality, and writing. Critics have also described Shrek as an antihero and noted the book's themes of satisfaction and self-esteem. The book served as the basis for the first Shrek film.

William Steig was an American cartoonist, illustrator and writer of children's books, best known for the picture book Shrek!, which inspired the film series of the same name, as well as others that included Sylvester and the Magic Pebble, Abel's Island, and Doctor De Soto. He was the U.S. nominee for both of the biennial, international Hans Christian Andersen Awards, as a children's book illustrator in 1982 and a writer in 1988.